A print zone in a printing context is the area of a media sheet where the printer may create an image of text, drawing or other data as required by a user. Controlling the print zone is an important design and operational criteria for a printer. Should the print zone be too short, then the user will not be able to print much material on a particular sheet. However, if the print zone is too large, then some of the printing may occur outside of the print zone and off of the actual sheet. In such a case, material such as footnotes, page numbers and the like may not be printed on the sheet which may lead to user dissatisfaction.
Some ways of controlling the print zone to ensure that data is printed on the sheet and not lost includes assuming a shorter print zone than might be able to be printed on a sheet therefore ensuring that the print zone always falls within the sheet. Another way of controlling the print zone is to use expensive optical sensors which may accurately detect the leading edge of a sheet which may then be used to adjust the print zone for the printer. However, optical sensors are very expensive and therefore increase the cost of the printing device to the users. Given the highly competitive market place for printing devices today, an increase in cost is a significant factor for manufacturers and consumers to consider.
Other factors that affect a print zone includes tolerances within the printer, tolerances within the sheet media and, in some circumstances, the speed with which the sheets are fed through the printing device. For example, as a printer is used there is some inherent wear in feed rollers, motor bearings and other parts which lead to variations in how a sheet is picked from the storage tray and fed through the printer. These variations may be sufficient to cause differences in the print zone over time. The differences in sheet media can also introduce variations which must be accounted for. In particular, different weights of paper may feed differently creating variations in how the printer feeds the sheet and therefore the resultant print zone. The speed with which the sheets are fed through the printing device can also be a factor as the gap between the trailing edge of a leading sheet and leading edge of a trailing sheet may become so small that errors in sensors may be introduced which leads to print zone variations. All these variations must be taken into account in the design and operation of a printing device to ensure that the print zone remains on a sheet.
Therefore, it would be advantageous, for a printing device to be able to adjust for changes that may occur such that the print zone from one page to another remains in an acceptable range for the user.